Reproductive age women fulfilling strict criteria for unexplained infertility (UI) will undergo a comprehensive neuroendocrinologic, hormonal and morphologic evaluation across two menstrual cycles to test whether UI is associated with abnormal pituitary secretion or response compared to fertile controls. Subjects will then be randomized to either three cycles of standard gonadotropin therapy or novel therapy with pituitary down-regulation followed by pulsatile gonadotropin-releasing hormone to test which therapy most approximate normal cycles.